It is known in the plastic molding art to use pressured molten plastic in conjunction with the molding of plastic articles. Conventionally, a mold includes a mold cavity for molding a product. However, before injecting the molten plastic into the mold cavity, air may be retained in the mold cavity. So, the air must be expelled from the mold cavity via an air channel. If not, surface quality of the molded product is decreased and the molded product may have flaws such as air holes, fissure, crazing, and so on.
It is desired to provide a mold for injection molding with an efficient air channel for expelling air from the mold cavity.